Minocycline and autoimmunity

Real-world management of juvenile autoimmune liver disease

Background and aims

Juvenile autoimmune liver disease (JAILD) includes paediatric forms of autoimmune hepatitis (AIH) and autoimmune sclerosing cholangitis (ASC). Since evidence is scarce, there are currently no evidence-based management guidelines for juvenile AIH. This survey was carried out amongst the paediatric members of the International AIH Group (IAIHG) to describe their practices in the management of JAILD.

Methods

An online survey questionnaire was distributed to members of the IAIHG with active practice (https://www.surveymonkey.de/r/Juvenile_AILD). The questionnaire consisted of four clinical scenarios on different presentations of AIH.

Results

Fifty-eight surveys were sent to the IAIHG members, out of which 43 (74%, 22 countries, four continents) were returned. None reported budesonide as a first-line induction agent for the acute presentation of AIH. Sixteen (37%) routinely perform liver biopsy at three years of biochemical remission. Thirty-five respondents (81%) perform magnetic resonance cholangiography (MRC) at presentation. Ciclosporin is the most widely used second-line agent (number of patients treated = ∼360, 21 centres). Mycophenolate mofetil (n = ∼225, 31 centres), tacrolimus (n = ∼130, 21 centres) and sirolimus (n = ∼5, 3 centres) are less often reported. Rescue therapy with infliximab and rituximab has been tried in eight centres (n = ∼19) and nine centres (n = ∼16), respectively.

Conclusions

Prednisolone remains the preferred first-line induction agent in JAILD. MRC at presentation is performed by the large majority of participants. Participants reported a wide variation in performing liver biopsy for therapy evaluation during follow-up. Within the paediatric members of the IAIHG there is considerable experience with second-line therapeutic agents.

Toward a noncytotoxic glioblastoma therapy: blocking MCP-1 with the MTZ Regimen

To improve the prognosis of glioblastoma, we developed an adjuvant treatment directed to a neglected aspect of glioblastoma growth, the contribution of nonmalignant monocyte lineage cells (MLCs) (monocyte, macrophage, microglia, dendritic cells) that infiltrated a main tumor mass. These nonmalignant cells contribute to glioblastoma growth and tumor homeostasis. MLCs comprise of approximately 10%-30% of glioblastoma by volume. After integration into the tumor mass, these become polarized toward an M2 immunosuppressive, pro-angiogenic phenotype that promotes continued tumor growth. Glioblastoma cells initiate and promote this process by synthesizing 13 kDa MCP-1 that attracts circulating monocytes to the tumor. Infiltrating monocytes, after polarizing toward an M2 phenotype, synthesize more MCP-1, forming an amplification loop. Three noncytotoxic drugs, an antibiotic - minocycline, an antihypertensive drug - telmisartan, and a bisphosphonate - zoledronic acid, have ancillary attributes of MCP-1 synthesis inhibition and could be re-purposed, singly or in combination, to inhibit or reverse MLC-mediated immunosuppression, angiogenesis, and other growth-enhancing aspects. Minocycline, telmisartan, and zoledronic acid - the MTZ Regimen - have low-toxicity profiles and could be added to standard radiotherapy and temozolomide. Re-purposing older drugs has advantages of established safety and low drug cost. Four core observations support this approach: 1) malignant glioblastoma cells require a reciprocal trophic relationship with nonmalignant macrophages or microglia to thrive; 2) glioblastoma cells secrete MCP-1 to start the cycle, attracting MLCs, which subsequently also secrete MCP-1 perpetuating the recruitment cycle; 3) increasing cytokine levels in the tumor environment generate further immunosuppression and tumor growth; and 4) MTZ regimen may impede MCP-1-driven processes, thereby interfering with glioblastoma growth.

Minocycline-induced black bone disease encountered during total knee arthroplasty

Finding discolored bone intraoperatively can be confusing and concerning to orthopedic surgeons. Multiple causes of pigmented bone exist, including ochronosis, metabolic bone diseases, metal deposits, sequestrum, metastatic disease, and minocycline use. Bone quality is an important consideration in intraoperative decision making with respect to components and fixation options in total joint arthroplasty. Abnormal bone encountered in routine arthroplasty can raise concerns over the integrity and healing potential of the bone when the etiology is uncertain.Minocycline is a drug routinely used for the treatment of acne, rosacea, and rheumatoid arthritis. Pigmentation is a commonly recognized adverse reaction associated with most of the drugs in the tetracycline family, affecting the skin, nails, teeth, oral mucosa, bones in the oral cavity, ocular structures, cartilage, thyroid, and other visceral structures.This article describes a case of pigmented bone secondary to minocycline use in a 55-year-old woman undergoing total knee arthroplasty. This entity has rarely been documented in the orthopedic literature; however, orthopedic surgeons should be aware of this side effect secondary to the widespread use of minocycline. Questions concerning the effect of minocycline on bone metabolism and structural integrity have yet to be fully answered, but an understanding and recognition of the entity will help guide surgeons with intraoperative decision making.

Drug-induced lupus erythematosus: incidence, management and prevention

The generation of autoantibodies and autoimmune diseases such as systemic lupus erythematosus has been associated with the use of certain drugs in humans. Early reports suggested that procainamide and hydralazine were associated with the highest risk of developing lupus, quinidine with a moderate risk and all other drugs were considered low or very low risk. More recently, drug-induced lupus has been associated with the use of the newer biological modulators such as tumour necrosis factor (TNF)-α inhibitors and interferons. The clinical features and laboratory findings of TNFα inhibitor-induced lupus are different from that of traditional drug-induced lupus or idiopathic lupus, and standardized criteria for the diagnosis of drug-induced lupus have not been established. The mechanism(s) responsible for the development of drug-induced lupus may vary depending on the drug or even on the patient. Besides lupus, other autoimmune diseases have been associated with drugs or toxins. Diagnosis of drug-induced lupus requires identification of a temporal relationship between drug administration and symptom development, and in traditional drug-induced lupus there must be no pre-existing lupus. Resolution of symptoms generally occurs after cessation of the drug. In this review, we will discuss those drugs that are more commonly associated with drug-induced lupus, with an emphasis on the new biologicals and the difficulty of making the diagnosis of drug-induced lupus against a backdrop of the autoimmune diseases that these drugs are used to treat. Stimulation of the immune system by these drugs to cause autoimmunity may in fact be associated with an increased effectiveness in treating the pathology for which they are prescribed, leading to the dilemma of deciding which is worse, the original disease or the adverse effect of the drug. Optimistically, one must hope that ongoing research in drug development and in pharmacogenetics will help to treat patients with the maximum effectiveness while minimizing side effects. Vigilance and early diagnosis are critical. The purpose of this review is to summarize the most recent developments in our understanding of the incidence, pathogenesis, diagnosis and treatment of drug-induced lupus.

Vasculitic neuropathy associated with minocycline use

INTRODUCTION

Minocycline is an antibiotic used for the treatment of acne. It has been associated with several autoimmune syndromes, including drug-induced lupus, autoimmune hepatitis, and vasculitis.

METHOD AND RESULTS

We report a case of a 28-year-old previously healthy woman who developed a left sciatic mononeuropathy 2 weeks after starting minocycline for acne. Magnetic resonance imaging studies supported the localization. A biopsy of the left sural nerve revealed acute nerve large arteriole necrotizing vasculitis. Her condition improved after the withdrawal of minocycline and a course of treatment with methylprednisolone.

CONCLUSION

This case provides further evidence that minocycline may induce a nonsystemic necrotizing vasculitis.

Drug-induced autoimmune-like hepatitis

The clinical phenotype of classical autoimmune hepatitis can be mimicked by idiosyncratic drug-induced liver injury, and differentiation can be difficult. The goals of this review are to enumerate the major agents of drug-induced autoimmune-like hepatitis, describe the clinical findings and risk factors associated with it, detail the clinical tools by which to assess causality, discuss putative pathogenic mechanisms, and describe treatment and outcome. The frequency of drug-induced autoimmune-like hepatitis among patients with classical features of autoimmune hepatitis is 9%. Minocycline and nitrofurantoin are implicated in 90% of cases. Female predominance, acute onset, and absence of cirrhosis at presentation are important clinical manifestations. Genetic factors affecting phase I and phase II transformations of the drug, polymorphisms that protect against cellular oxidative stress, and human leukocyte antigens that modulate the immune response may be important pathogenic components. Clinical judgment is the mainstay of diagnosis as structured diagnostic methods for drug-induced liver injury are imperfect. The covalent binding of a reactive drug metabolite to a hepatocyte surface protein (commonly a phase I or phase II enzyme), formation of a neoantigen, activation of CD8 T lymphocytes with nonselective antigen receptors, and deficient immune regulatory mechanisms are the main bases for a transient loss of self-tolerance. Discontinuation of the offending drug is the essential treatment. Spontaneous improvement usually ensues within 1 month. Corticosteroid therapy is warranted for symptomatic severe disease, and it is almost invariably effective. Relapse after corticosteroid withdrawal probably does not occur, and its absence distinguishes drug-induced disease from classical autoimmune hepatitis.

Emerging drugs for acne

Acne vulgaris is a common skin disorder that affects most individuals at some point in their lives. It may result in significant morbidity, including cutaneous scarring and psychological impairment. Current treatments include topical retinoids, benzoyl peroxide, topical and systemic antibiotics, and systemic isotretinoin. There are growing concerns of rising antibiotic resistance, significant side effects of isotretinoin therapy, and lack of safe and effective treatment for pregnant females. Recent advances in the pathogenesis of acne have led to a greater understanding of the underlying inflammatory mechanisms and the role the Propionibacterium acnes and biofilms. This has led to the development of new therapeutic targets. This article reviews emerging treatments of acne, including topical picolinic acid, topical antibiotic dapsone, systemic zinc salts, oral antibiotic lymecycline, new formulations of and synergistic combinations of benzoyl peroxide, photodynamic therapy with topical photosensitizers and potential acne vaccines.

Minocycline-induced drug hypersensitivity syndrome followed by multiple autoimmune sequelae

BACKGROUND

Drug hypersensitivity syndrome (DHS) is a severe, multisystem adverse drug reaction that may occur following the use of numerous medications, including anticonvulsants, sulfonamides, and minocycline hydrochloride. Long-term autoimmune sequelae of DHS have been reported, including hypothyroidism.

OBSERVATIONS

A 15-year-old female adolescent developed DHS 4 weeks after starting minocycline therapy for acne vulgaris. Seven weeks later she developed autoimmune hyperthyroidism (Graves disease), and 7 months after discontinuing minocycline therapy she developed autoimmune type 1 diabetes mellitus. In addition, she developed elevated titers of several markers of systemic autoimmune disease, including antinuclear, anti-Sjögren syndrome A, and anti-Smith antibodies.

CONCLUSIONS

Minocycline-associated DHS may be associated with multiple autoimmune sequelae, including thyroid disease, type 1 diabetes mellitus, and elevated markers of systemic autoimmunity. Long-term follow-up is needed in patients with DHS to determine the natural history of DHS-associated sequelae.

Characterising vancomycin's immunotoxic profile using Swiss and CFW mice as an experimental model

Immunotoxicology can lead to determining the adverse effects of different compounds on the immune system. Sometimes, many drugs (especially antibiotics) induce immune alterations, mainly auto-immunity. This study was aimed at determining vancomycin's immunotoxic effect by comparing the original molecule to two of the most used copies. Thirty-two mice from two murine strains (Swiss and CFW) were treated with three antibiotic formulations for studying its effect on splenic lymphoid and peripheral blood cell populations by using haemograms, flow cytometry and blastogenesis assays. The results indicated that vancomycin produces neutropenia and lymphocytosis in peripheral populations and that it induces a selective immunomodulatory effect on splenocyte sub-populations, depending on formulation and the strain so treated.

Chronic minocycline-induced autoimmunity in children

OBJECTIVE

To report our experience with minocycline-induced autoimmunity (MIA) in children, with an emphasis on the potential for chronicity.

STUDY DESIGN

Retrospective cohort study of patients with development of rheumatologic symptoms while receiving minocycline between 1996 and 2006.

RESULTS

Twenty-seven children were diagnosed with MIA at a single pediatric rheumatology practice. The mean age at onset was 16.5 +/- 1.39 years. The mean duration of minocycline use before diagnosis was 13.0 +/- 10.8 months. All patients presented with constitutional symptoms. Twenty-two had polyarthralgia, and 17 had polyarthritis, mostly affecting hands and feet. On the basis of disease duration after discontinuation of minocycline, we divided subjects into 3 categories: transient, intermediate, and chronic. Seven patients had development of chronic autoimmune disease that was still active at last follow-up, a mean of 31.6 +/- 13.0 (13-48) months after onset. Six patients followed an intermediate course, with resolution of symptoms within 12 months, and 14 patients had symptoms that resolved rapidly on discontinuation of minocycline. All patients with a chronic course had evidence of arthritis at presentation.

CONCLUSION

A substantial proportion of children with MIA had development of chronic symptoms with the potential for significant morbidity. Physicians who prescribe minocycline should be aware of its propensity for inducing potentially serious autoimmune phenomena.

Minocycline hepatitis

Minocycline is an effective antibiotic widely used in the treatment of acne vulgaris. We report a previously well 20-year-old woman who developed liver dysfunction with jaundice and malaise following a 1 year course of minocycline for acne vulgaris. Serum antinuclear antibody was strongly positive (1 : 2560) and liver transaminases were grossly deranged. All other causes of liver disease were excluded. Both the clinical symptoms and laboratory abnormalities resolved spontaneously on stopping the drug. We review the three different types of hepatotoxicity associated with minocycline and draw evidence to support the diagnosis of minocycline-induced autoimmune hepatitis. This case supports the call to monitor patients on minocycline therapy for autoimmune disease of the liver and highlights the need for a multicentre prospective trial of the risks and benefits of long-term minocycline therapy.

Drug-induced arthritic and connective tissue disorders

OBJECTIVES

All pharmacologic agents have the potential for both benefit and toxicity. Among the more interesting and important adverse consequences of drug therapy are a range of joint and connective tissue complaints that may mimic or reproduce primary rheumatologic diseases. In this article, we review the literature on commonly used drugs reported to induce arthritis and/or connective tissue-based diseases. We assess the strength of the reported associations, discuss diagnostic features and treatment implications, and consider possible mechanisms for drug-induced genesis of rheumatic conditions.

METHODS

We reviewed the Medline database from 1987 to 2006 to identify drug-induced arthritic and connective-tissue disease syndromes, utilizing 48 search terms. A qualitative review was performed after the articles were abstracted and the relevant information was organized.

RESULTS

Three hundred fifty-seven articles of possible relevance were identified. Two hundred eleven publications were included in the final analysis (case series and reports, clinical trials, and reviews). Many drugs were identified as mimicking existing rheumatic conditions, including both well-established small molecules (eg, sulfasalazine) and recently introduced biologic agents (eg, antitumor necrosis factor agents). The most commonly reported drug-induced rheumatic conditions were lupus-like syndromes. Arthritis and vasculitis were also often reported.

CONCLUSIONS

Drug-induced rheumatic syndromes are manifold and offer the clinician an opportunity to define an illness that may remit with discontinuation of the offending agent. Early diagnosis and withdrawal of the drug may prevent unnecessary morbidity and disability.

Hyperthyroidism and lupus-like syndrome in an adolescent treated with minocycline for acne vulgaris

Minocycline is a tetracycline antibiotic commonly used in the treatment of acne. While it is generally considered to be a safe medicine, a number of side effects have been associated with its use. We describe an adolescent boy who developed hyperthyroidism and a drug-induced lupus-like syndrome following minocycline treatment for his acne.

Is minocycline therapy in acne associated with antineutrophil cytoplasmic antibody positivity? A cross-sectional study

BACKGROUND

Minocycline (MN), one of the commonly prescribed therapies for acne, is known to be associated with autoimmune disorders including drug-induced lupus. However, data are sparse regarding the prevalence of autoimmune disease in acne or in patients with acne treated with MN.

OBJECTIVES

To establish the prevalence of antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies (ANCA) and new autoimmune syndromes in an MN-exposed and unexposed population with acne.

METHODS

In a cross-sectional study, 252 patients with acne vulgaris were assessed. Sixty-nine per cent had been exposed to MN at some point or were taking the drug at the time of the interview. Data recorded included duration of disease (acne) and drug history as well as possible side-effects of drugs, in particular joint symptoms (pain and swelling). In addition, blood was taken for ANA, ANCA, liver function tests and HLA analysis.

RESULTS

There was no statistical difference in the prevalence of ANA positivity between patients exposed (13%) or not exposed (11%) to MN. However, higher titres of ANA (1/160 or higher) were found in the MN-exposed group (45% compared with 12% in the unexposed group). ANCA positivity was found in 7% of the MN-exposed group but no positivity was found in the unexposed cohort (P = 0.022). In 58% of cases, the ANCA detected were of the perinuclear pattern (p-ANCA) with myeloperoxidase specificity, and this finding was associated with clinical symptoms in the majority of cases. Two p-ANCA-positive patients were thought in retrospect to have developed a drug-induced lupus syndrome.

CONCLUSIONS

ANA positivity is seen in patients with acne irrespective of exposure to MN; however, p-ANCA appear to be a serological marker for developing autoimmune disease in patients receiving MN.

Minocycline-induced lupus in adolescents: clinical implications for physical therapists

STUDY DESIGN

Resident's case problem.

BACKGROUND

In the United States, minocycline is a frequently prescribed medication for the treatment of moderate to severe acne, a common condition in adolescents. The use of minocycline has been associated with severe adverse effects that frequently comprise a musculoskeletal component, including drug-induced lupus. Physical therapists have the responsibility to identify drug reactions that mimic musculoskeletal symptoms. The patient described herein was a 15-year-old adolescent boy who had taken minocycline for 14 days. He was initially treated by his primary physician on the 15th day of minocycline therapy for symptoms of fever, joint swelling, and a rash. The patient presented to a physical therapist on the 22nd day with complaints of severe myalgia, arthralgia, and severely limited mobility secondary to pain. The patient was referred to a pediatric rheumatologist because of the systemic nature and severity of the symptoms.

DIAGNOSIS

The patient was subsequently diagnosed as having drug-induced lupus by a pediatric rheumatologist. The patient's myalgia and arthralgia subsided within 6 weeks, but his strength, coordination, and endurance did not reach their prior levels for 3 to 4 months.

DISCUSSION

Physical therapists who include a comprehensive pharmacovigilance component in their patient examination may recognize musculoskeletal symptoms that arise from a nonmusculoskeletal origin. Minocycline is commonly prescribed in the United States as an antibiotic and for treatment of acne and rheumatoid arthritis. Therefore, physical therapists should screen for minocycline use when an adolescent patient or a patient with rheumatoid arthritis presents with diffuse musculoskeletal symptoms. An automated medication monitoring system would provide physical therapists with a means of accessing current information on medication use.

Etiological role of brucellosis in autoimmune hepatitis

To show that brucellosis may trigger autoimmune hepatitis (AIH), in addition to nonspecific liver involvement and toxic hepatitis, due to a class effect of tetracycline family used for treatment. We present a female patient admitted to our hospital due to partially improved fatigue and elevated liver enzymes following doxycycline and streptomycin usage for brucellosis. Brucellosis is endemic in our country, Turkey. It may involve any organ in the body. Liver is frequently involved. Doxycycline used for treatment occasionally may lead to hepatotoxicity. AIH is a necroinflammatory disease of the liver. Certain drugs (e.g., minocycline), toxins, and viruses (hepatitis B, hepatitis C, EBV, etc.) can trigger AIH. Only one case of AIH probably caused by doxycycline and brucellosis was reported. We discuss the relationship between brucellosis, AIH, and hepatotoxicity of doxycycline. Brucellosis may trigger AIH.

Cytokine release does not improve the sensitivity and specificity of the direct popliteal lymph node assay

The popliteal lymph node assay (PLNA) is being considered as a tool to predict the potential of drugs for inducing systemic autoimmune and hypersensitivity reactions. Despite the use of different technical approaches and the evaluation of over 130 compounds, the sensitivity and specificity of the PLNA are still debatable due to many false positive and negative responses. In this study, cytokine production was assessed as a possible endpoint to improve the direct (primary) PLNA. Diclofenac, imipramine, hydralazine, glafenin and minocycline were tested using the classical procedure. TH1 cytokines (IL-2 and IFN-gamma), TH2 cytokines (IL-4 and IL-5) and pro-inflammatory cytokines (IL-6, TNF-alpha, monocyte chemoattractant protein-1 (MCP-1), IL-12p70 and IL-10) were measured in the serum and in suspensions of popliteal lymph node cells of female Balb/c mice by flow cytometry 7 days after drug administration. Only diclofenac and imipramine induced a cellularity index above 5 (considered as a positive response). Of the five tested drugs, only diclofenac induced a slight increase in TH1 cytokines, but there were no effects on TH2 cytokine production whatever the drug tested. Diclofenac increased the production of pro-inflammatory cytokines, whereas the production of MCP-1 was increased by minocycline and decreased by imipramine. No changes in serum cytokine levels were evident. These results suggest that measuring cytokine release is unlikely to improve the sensitivity and specificity of the direct PLNA.

Drug-induced vasculitis

Therapeutic agents from virtually every pharmacological class have been implicated in the development of drug-induced vasculitis. Clinical manifestations range from small vessel hypersensitivity vasculitis and leukocytoclastic vasculitis to clinical syndromes indistinguishable from classical systemic forms of vasculitis such as Wegener's granulomatosis, polyarteritis nodosa and Churg-Strauss syndrome (CSS). The exact pathogenic mechanisms involved remain to be elucidated; but both cell-mediated and humoral immunity appear to play important roles. Affected individuals may present with cutaneous involvement alone or life-threatening systemic involvement, which may result in severe and sometimes fatal illness. Since clinical presentation as well as serological and pathological parameters is identical to idiopathic forms of vasculitis, a high index of suspicion is necessary to accurately and expeditiously diagnose drug-induced vasculitis. Withdrawal of the offending agent alone is often sufficient to induce prompt resolution of clinical manifestations, obviating the need for systemic corticosteroids or more powerful forms of immunosuppression.

In vitro response of human gingival epithelioid S-G cells to minocycline

Minocycline, a broad-spectrum antibiotic used in the treatment of acne and periodontal disease and to control inflammatory diseases such as rheumatoid arthritis, has recently been shown to induce a spectrum of adverse health effects. In the light of these contradictory data, this research was directed to provide basic information on the toxicology of minocycline, using in vitro cell culture models, and to evaluate its efficacy in periodontal therapies, particularly for wound healing. The human gingival epithelioid S-G cell line was used as the bioindicator. The greater toxicity of minocycline over doxycycline and tetracycline, related antimicrobial agents, probably correlated with its higher lipophilicity. The cytotoxicity of minocycline was unaffected by an S9 hepatic microsomal fraction, indicating that it is a direct-acting, rather than a metabolism-mediated, cytotoxicant. In comparative toxicity studies, much variation in the degree of sensitivity to minocycline was noted for different cell types. No correlation in the extent of sensitivity to minocycline and the physiologic state of the bioindicator cell (normal, transformed or malignant) was noted. The toxicity of minocycline to the S-G cells was dependent on its concentration and length of exposure. For a continuous 3-day exposure of the S-G cells to minocycline, the midpoint cytotoxicity (or, NR(50)) value, as quantified in the neutral red (NR) assay, was 204 microg/ml on day 1, 84 microg/ml on day 2, and 59 microg/ml on day 3. For a 1-h exposure of the S-G cells in phosphate buffered saline (PBS), the NR(50) value was 780 microg/ml minocycline. Although a 1-h exposure in PBS to 200 microg/ml minocycline exerted some toxicity, the S-G cells recovered on exposure to growth medium; irreversible, progressive damage occurred at 400 microg/ml minocycline and greater. Minocycline, at 50 microg/ml, enhanced attachment of the S-G cells to a gelatin-coated surface and cell migration towards an immobilized fibronectin gradient, both biologic parameters important in periodontal wound healing. Minocycline generally had little or no effect on production of the pro-inflammatory cytokines, interleukin-6 (IL-6) and interleukin-8 (IL-8), by non-activated S-G cells, the exception being stimulation of IL-6 at 48 h. IL-1beta, however, greatly stimulated IL-6 and IL-8 production, which was further increased by concurrent exposure to minocycline. This suggested that minocycline may enhance the ability of gingival epithelial cells to participate in the early, inflammatory phase of periodontal wound healing. The limitation of minocycline efficacy to a rather narrow window of concentration, centering about 50 microg/ml, and primarily for short-term exposures may possibly explain, in part, the contradictory clinical data on the health effects of this drug.

Drug-induced vasculitis

Many therapeutic agents, including recently introduced biologic response modifiers, can induce a variety of vasculitic manifestations ranging from small vessel hypersensitivity vasculitis and leukocytoclastic vasculitis to distinct vasculitic syndromes such as Wegener's granulomatosis, polyarteritis nodosa, and Churg Strauss syndrome. The pathogenic mechanisms remain to be defined and appear to be multifactorial, with cell-mediated and humural immune mechanisms playing important roles. Clinical presentation varies in severity from mild to severe and even fatal illness, can be self-limiting, or follows a more chronic protracted course. There are no significant differences in clinical presentation, serologic abnormalities, and pathologic findings with the idiopathic forms of vasculitis. However, it is extremely important to identify the offending drug because the discontinuation of the drug is often followed by a rapid improvement of the underlying vasculitic disorder.

Autoimmune liver disease

Autoimmune hepatitis in children may be associated with sclerosing cholangitis in the absence of inflammatory bowel disease. Wilson disease can have clinical and laboratory features that resemble autoimmune hepatitis, and it may respond initially to corticosteroids. Soluble HLA-DR antigens reflect clinical activity, and they may be useful markers of treatment response. Polymorphisms of the cytotoxic T lymphocyte antigen-4 gene may synergize with other autoimmune promoters or HLA risk factors to increase susceptibility and alter disease expression. DRB1*1301 distinguishes Argentine children from Argentine adults and identifies a unique subgroup. Antibodies to soluble liver antigen/liver-pancreas do not characterize a separate clinical entity. Their target antigen has been isolated, and it shares homologies with a selenocysteine-specific protecting factor (tRNP((Ser)Sec)). CYP2D6 is expressed on the hepatocyte surface, and it can be targeted by antibodies in autoimmune hepatitis and chronic hepatitis C. Perinuclear antineutrophil cytoplasmic antibodies lack sensitivity and specificity for autoimmune hepatitis, and they have diverse antigen specificities. Activation-induced cell death may be impaired in autoimmune hepatitis, and, in contrast to budesonide, mycophenolate mofetil has been effective in a small study of problematic patients.